JP5542954B2 - Electromagnetically operated valve - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically operated valve having an electromagnetic actuator and a method for manufacturing a part of the electromagnetic actuator. The electromagnetically operated valve is in particular a fuel injection valve, and the component of the electromagnetic actuator is, for example, an armature.

  The high pressure injection valve of the prior art is basically configured as a conventional electromagnetic switching valve having a coil and parts of an electromagnetic actuator. The parts of the electromagnetic actuator are, for example, an armature, an internal magnetic pole, an external magnetic pole, etc., and are manufactured as a turning part from a soft magnetic ingot material. Due to the electrical properties of this material and the 360 ° closed contours of the parts of the electromagnetic actuator, eddy current losses occur when a magnetic field is formed or disappears during operation, thereby switching the fuel injection valve switching time or dynamics. Will fall.

DISCLOSURE OF THE INVENTION On the other hand, the electromagnetically operated valve according to the present invention having the configuration described in claim 1 has a magnetic field when a component such as an armature and / or an internal magnetic pole and / or an external magnetic pole of an electromagnetic actuator is used. This has the advantage that the eddy current loss when changed can be remarkably reduced and the switching time of the valve can be remarkably shortened. In the present invention, this means that at least one part of the electromagnetic actuator of the valve has a plurality of fan-shaped portions made of a soft magnetic material and a plurality of insulating separating webs, each having two adjacent fan-shaped portions. One separating web is provided between the parts, and each one separating web is realized by a configuration in which each two adjacent sector parts are completely electrically separated from each other. Thus, the electromagnetic actuator component has at least two soft magnetic sectors and two insulating separating webs.

  Advantageous embodiments of the invention are described in the dependent claims.

  Advantageously, the separating web is made from a material comprising ceramic. Due to the non-conductive nature of the ceramic material, a reliable electrical separation or insulation of the individual mutually contacting sectors of the parts of the electromagnetic actuator is ensured.

  More advantageously, at least one part of the electromagnetic actuator of the valve has exactly four sectors and four separating webs. Thereby, eddy current loss when the magnetic field changes can be remarkably reduced with only a small number of fan portions and separation webs.

  In another advantageous embodiment, the width of the separating web is chosen to be the marginal width that ensures that adjacent sectors are electrically separated from one another. By reducing the width of the separating web and the proportion of material in this way, the loss of the soft magnetic material of the armature is negligible, so that the strength of the magnetic circuit is kept substantially constant. Guaranteed.

  Advantageously, at least one part of the electromagnetic actuator is produced by the PIM method (powder injection molding method). By using such a multi-material powder injection process instead of the turning process, it is possible to easily manufacture parts of the electromagnetic actuator with a short manufacturing time and a low individual product cost. In one embodiment of the method of the invention, an insulating separating web is produced in a first step, after which the insulating separating web is mechanically held on a tool and then a sector made of soft magnetic material. The part can be injection molded. Alternatively, a soft magnetic sector can be created in the first step. Next, the sector is placed on a tool, the sector is held in place using a magnetic field, and the separation web is injection molded into the space between the soft magnetic sectors in the next step. . Thus, in the present invention, a component for an electromagnetic actuator having a thin wall separating web which is non-conductive between the soft magnetic sectors can be manufactured at low cost. This can reduce the formation of eddy currents against magnetic field formation and magnetic field disappearance. In that case, the separating web must be formed as thin as possible so that the loss of the volume of the magnetic material which adversely affects the realizable magnetic force is reduced. For the first time, the method of the present invention puts a manufacturing method that requires relatively many requirements in the above-mentioned case into practical use in terms of manufacturing technology. This is because in order to be able to produce the other member by the injection process, they must be held with a space between the separating webs or between the soft magnetic sectors. Therefore, in the present invention, the electromagnetic actuator can be manufactured by the multi-material PIM method of one or more parts such as an armature, a magnetic core or an internal magnetic pole, or a valve jacket or an external magnetic pole (a yoke member). . In this case, it is particularly advantageous that the soft magnetic sector can be produced by metal injection molding (MIM). The insulating separating web can advantageously be produced by a ceramic injection molding method (CIM method, CIM = Ceramic Injection Molding). Since the soft magnetic sector can be positioned in the injection molding tool by magnetic force, a space for injection molding the insulating separating web is obtained between the soft magnetic sectors. The separating web can be mechanically held in an injection molding tool. This makes it possible to realize a very economical manufacturing method.

  According to the method of the present invention for producing an electromagnetic actuator part having a large number of sectors made of soft magnetic material and a large number of insulating separating webs by the PIM method, the switching time, in particular the cut-off time, is greatly reduced. Parts can be produced economically, which significantly reduces the amount of fuel to be injected into the combustion chamber, for example when used in a vehicle. By reducing the injection amount in this way, the idling characteristic of the engine is improved, and the multiple injections of the fuel injection valve can be improved. As a result, the exhaust gas characteristics of the engine are remarkably improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, taking an armature as an example.

It is a schematic sectional drawing of the armature of a fuel injection valve. It is a perspective view of the armature of the fuel injection valve of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, referring to FIGS. 1 and 2, a fuel injection valve for injecting fuel and an armature of an electromagnetic actuator of the fuel injection valve 1 according to an advantageous embodiment of the present invention will be described. The manufacturing method will be described in detail.

  As can be seen from the perspective view of FIG. 1, the fuel injection valve includes an armature 3, a magnetic pole core 31, a valve jacket 32 that is a yoke member, and a coil 2 that surrounds the armature 3. including. The armature 3 made of a soft magnetic material has a through-hole 6 arranged in the axial direction A at the center, and a valve needle not shown in the figure is arranged in the through-hole 6. Furthermore, the armature 3 has four fuel openings 7 extending in the axial direction A, and each fuel opening 7 is provided in one of the four fan-shaped portions 4. Further, as shown in FIG. 2, each sector 4 has substantially a quarter of the volume of the armature 3 in the circumferential direction. Insulating separating webs 5 made of ceramic material are arranged between two adjacent sector parts 4, and each separating web 5 electrically isolates or insulates adjacent sector parts 4 from each other. . Unlike the embodiment shown in the drawing, the number of the fan-shaped portions 4 or the separation webs 5 can be appropriately changed according to the desired operation of the armature 3 in the fuel injection valve 1, but at least two separation webs are provided. Provided.

The parts of the electromagnetic actuator are manufactured by a multi-material powder injection molding method (PIM method). In that case, there are two alternative methods as a method for manufacturing a part such as an armature. Since the part is composed of two parts groups, i.e. a sector 4 and a separating web 5, in the first step, the first part group of both parts groups is preferably produced by injection. can do. In that case, the first part group is positioned in the injection molding tool in the next step, and then the second part group is injection molded into the space between the first part groups by injection method. To do. In the case where the first group of parts is an insulating separating web 5, this insulating separating web 5 is mechanically held in an injection molding tool, and then the metal is formed between the separating webs 5 by a metal injection molding method. The soft magnetic sector 4 is injection molded. When the first part group is the soft magnetic sector 4, the sector 4 is manufactured by a metal injection molding method and then held by a magnetic field in an injection molding tool. Thereafter, the separation web 5 is injection-molded by a ceramic injection molding method in the space between the soft magnetic sector-shaped parts 4. A powder injection molding method is preferably used as the injection molding method.

  The above-described valve of the present invention and the manufacturing method of the present invention for manufacturing electromagnetic actuator components reduce eddy current loss, and in particular, the dynamic characteristics desired and required in the high-pressure injection valve are markedly increased. Improvements and this improvement in dynamics characteristics significantly improve engine fuel consumption and emissions characteristics.

Claims (6)

An electromagnetically operated valve including an electromagnetic actuator having an armature (3),
The armature (3) of the electromagnetic actuator has a plurality of fan-shaped portions (4) made of a soft magnetic material and a plurality of insulating separating webs (5).
The separating web (5) is arranged between each two adjacent sector parts (4), and the separating web (5) electrically connects each two adjacent sector parts (4) to each other. In a completely separate valve,
The armature (3) has a through hole (6) in the center,
A valve needle is disposed in the through-hole (6),
The fan-shaped parts (4) are arranged in the circumferential direction with the separating web (5) interposed therebetween,
The separating web (5) is made of a material containing ceramic,
A valve, characterized in that a fuel opening (7) is provided in the fan-shaped part (4) of the armature (3) . The armature (3) has four fan sections (4) and four separation webs (5).
Claim 1 Symbol mounting of the valve. The soft magnetic sector (4) of the armature (3) is produced by a metal injection molding method (MIM = Metal Injection Molding) .
The valve according to claim 1 or 2 . The valve is a fuel injection valve;
The valve according to any one of claims 1 to 3 . A method for manufacturing an armature (3) of an electromagnetic actuator,
The armature (3) is produced from two different component groups, which are a component group having a plurality of sectors (4) made of soft magnetic material and a component group having a plurality of insulating separating webs (5). In the manufacturing method,
In the first step, a first part group is produced out of both parts groups, the first part group is placed in the injection molding tool, and in the second step, the second part out of both parts groups. Group injection molding,
In the second step,
When the first part group is the insulating separating web (5), the insulating separating web (5) is mechanically held in the injection molding tool, and the soft part is formed by a metal injection molding method. A magnetic sector (4) is injection molded between the separating webs (5);
When the first part group is the soft magnetic sector (4), the soft magnetic sector (4) is held in the injection molding tool by a magnetic force, and the separation web is formed by a ceramic injection molding method. (5) A method of manufacturing, characterized in that injection molding is performed between the soft magnetic sector parts (4). Producing the first part group and / or the second part group by a powder injection molding method;
The manufacturing method of Claim 5 .

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